Railway track and track-swtich heater



Oct. 13, 1936. w. P. SCHOLZ RAILWAY TRACK AND TRACK SWITCH HEATER Filed April 12, 1934 2 Sheets-Sheet 2 ow/W 2 a W9 ,M E: "w w M w w 1 H y a J. p H WWW. m W1" H J 0 w i z: w z may l mmnunu 4+ n u w u u I "Inla "'1',"11.111111111111111] INVENTOR Z'MW ATTORNEYS Patented Oct. 13, 1936 UNITED STATES PATENT OFFICE William P. Scholz, Morristown, N. J.

Application April 12, 1934, Serial No. 720,156

7 Claims.

This invention relates to improvements in electric heating apparatus adapted to be employed as a means of melting snow in locations such as might interfere with the operation of railway switches or with the running of trains over railway tracks. The invention includes not only a heater of the above-described character, but also relates to means whereby the heater may be mounted at a predetermined distance below the top of a railway tie and adjusted as to its position in a direction lengthwise of the tie.

It is an object of the invention to provide a heater of the above-described character the electric elements of which may be hermetically sealed in a container surrounded by a jacket provided with air inlet and outlet orifices so arranged as to cause the heater to disseminate energy by convection dependent upon air circulation, as well as by radiation.

A second object of the invention is to provide the outlet orifice of the jacketed portion of the heater with one or more bafile-plates or vanes so disposed as to oppose a reversal of the air current through the heater and to cause the current of air to be circulated about the heating element and expelled from the outlet orifice along paths and in directions such as to most effectively absorb the energy generated by the electric heating element and carry it to those parts of the switch mechanism in which the presence of snow is most damaging.

A third object of the invention is to provide a heater of the above-described character with a novel type of mounting bar by which it may be secured to a railway tie at a predetermined distance below its upper surface and adjusted'to any one of a number of positions in a direction lengthwise of the tie.

A fourth object of the invention is to provide the heater with a thermally-controlled switch and switch connections whereby the rate of energy supplied by the heating element may be automatically varied in a manner such as to enhance the effectiveness of the heater as a means of removing snow from a railway switch and then keep it clear of snow throughout the duration of a storm.

A fifth object of the invention is to provide a novel form of thermally-controlled switch having its switch contacts thoroughly insulated and enclosed within a refractory container but with its thermally sensitive switch-operating device mounted on the outside of the container so as to be quickly responsive to changes of temperature in the surrounding atmosphere.

It is a sixth object of the invention to provide means whereby variations of temperature in the surrounding atmosphere may be communicated to the temperature sensitive element of the switch by means of air circulation as well as by radiation, 5 in order to shorten the time element of lag between variations of temperature and the responsive operation of the switch.

It is a seventh object of the invention to provide novel means whereby the time element of 10 lag between changes of temperature of the atmosphere and the response of the switch may be readily adjusted.

It is an eighth object of the invention to provide the switch with a circuit-closing element in 15" which a carbon contact may be used as a means of lessening the detrimental efiect due to arcing on the opening of the switch Without making the carbon'contact of unduly massive proportions.

-In the accompanying drawings illustrating preferred and modified forms of the above-described invention,-

Figure 1 is a perspective view of a heater and a heater-attaching device secured to a railway tie, of'which a portion is broken away to disclose underlying structure.

Fig. 2 is a plan view of the heater with parts shown in horizontal, longitudinal cross-section.

Fig. 3 is a transverse, sectional view taken through the heater on the line 33 of Fig. 2 and viewed in the direction indicated by the arrows.

Fig. 4 .is a large-scale, vertical, longitudinal, cross-sectional view of a portion of the heater including the automatic thermal controlling switch. 35

Fig. 5 is a transverse, sectional view through the controlling switch and adjacent portions of the heater, the section being taken along the line 5-5 of Fig. 4 and viewed in the direction indicated by the arrows. 0.

Fig. 6 is a transverse, sectional view through the switch and adjacent portions of the heater, the section being taken along the line 6-'6 of Fig. 4 and viewed in the direction indicated by the arrows. 45

. Fig. '7 is a transverse, sectional view, the section being taken near one end of the heater along the line l'--'l of Fig. 2 and viewed in the direction indicated by the arrows.

Fig. 8 is a plan of a portion of a railway switch indicating positions in which heaters embodying the invention might be effectively mounted.

Fig. 9 is a longitudinal, cross-sectional view through a thermomotive element of modified form which mightbe substituted for the one 55 illustrated by Fig. 4, the form shown in Fig. 9 including means for adjusting the time element of the switch of which it is used as a part.

A form of electric heater adapted for use as a railway track switch snow-melting device may, in general, comprise electric heating coils 20, 20 (Fig. 2), mounted within a container 2| having threaded caps 22, 23 (Figs. 1 and 2), which may be removed torender the parts of the device within the container accessible.

The container 2| may be enclosed within a jacket 24 having one or more openings 25 (Figs. 1 and 3) so positioned as to provide for the admission of air to the jacket, and one or more outlet orifices, which may preferably comprise openings in a removable fitting 26, may be provided to permit heated air to be ejected from the jacketed portion of the heater. L

In order that the heater may be secured to a railway tie at a predetermined distance below its upper surface and adjusted to any desired position in a direction lengthwise of the tie, the heater may be provided with lugs 21 (Figs. 1 and 3) having undercut recesses 28 of a form such as to be held in engagement with a flanged rib 29 on a heater-attaching bar 30, which may be secured to the side of a railway tie 3|, a portion only of which is illustrated inFigs. 1 and 3, by means of spikes 32, or other suitable fastening devices, which may be passed through openings 33 in the bar.

The attaching bar may have one portionextended upwardly and then laterally to a position such as to make contact with the upper surface of a railway tie when the bar is at the desired position below its upper surface. In the form of the invention herein disclosed the bar is curved upwardly at one end as at 34 and then extended laterally to provide a lug 35 which maybe secured to the upper surface of .the tie by means of a spike or other suitable fastening device 96.

It will be apparent that the connection between the flanged rib of the attaching bar and the recessed lugs of the heater is such as to permit the heater to be shifted endwise to any desired position in which it may be held .byany appropriate.

means, such, for example, as a set screw 31 (Figs. 1 and 2), in a lug 38, the bar 30' being provided with spaced recesses 39 (Fig. 2). to receive the end of the set screw.

.Preferably the heater will beprovidedl with recessed lugs on opposite sides, as indicated in Fig. 3, in order that itmay be applied to either side of a tie with either end of the heater in a desired direction. 9

.Thenumber of heaters to be usedin protecting any particular switch and the location of the heaters with respect to parts of the switch may vary in accordance withthe locationof the switch and the character of weather conditions which it may be anticipated will have to be dealt with. In Fig. 8 is illustrated a fragmentary portion of a railway switch construction comprising ties 3| to which are secured rails 4| and their associated switch-points 42 connected by cross-bars 43 and shiftable laterally over bearing plates 44, secured to the ties, by means of any appropriate switching mechanism (not disclosed). The heaters designated generally by reference character v45 maybe secured to the ties in such positions as may be best adapted to direct heated air into the spaces between the rails 4i and switch-points 42 and against the bearing plates 44 over which the rails are shifted. The heaters will be so positioned by the attaching bars 30 asto leave a clear space between the tops of the heaters and the lower surfaces of the rail, and the size of the heater isv such that it may be kept clear of the connecting bars 43 and any other metal parts of the switch construction inorder to avoid electrolysis or short-circuiting, or other interference with any of the conductive portions of the railroad construction used in the transmission of electrical energy for any purpose whatever. It has been found practicable to apply to each switch-point a group of heaters which may be connected in series, the combined resistance of the group being such that, when connected with the terminals 'of an available source of electromotive force, the strength of current through the heaters will be limited to that necessary to supply the desired amount of energy. Successful results have been attained by distributing nine heaters along each switch-point of a pair and connecting them in series across the terminals of a 500-volt source of electromotive force.

The air inlet openings 25 should preferably'be located in the lower part of the jacket. They may, for example, be spaced along the lower portion of one of the end walls as indicated in Figs. 1 and 3.

The air outlet should be such as to cause the air within the jacket to move along paths such that it will most efiectively absorb heat energy from the container surrounding the heating element. In the form. of the invention herein disclosed the outlet is provided with ,a separate fitting 26 having bafile-plates or vanes so disposed as to have, the desired efiect upon the air currents within the jacket and also shield the outlet from the evil effects of unfavorable external air currents. As best illustrated by Figs. 1 and 3 the outlet fitting comprises an arcuate plate 46, which may be secured to the outer wall of the jacket at one side of the longitudinal plane passing through its axis. Leading inwardly from the portions of this plate surrounding the two outlet openings 41, 48, is a tubular structure 49, the lower wall 50 of which serves as a baflle-plateto deflect air currents rising in the left side of the jacket towards the center of the heater, after which the air may flow over the inner edge of the plate and to and through the outlet orifices as indicated by arrows in'Fig. 3. The end walls of the tubular structure 49 also serve as baffle-plates to prevent air currents rising in the end portions of the left side of the jacket from passing directly through the outlet orifices without first being deflected inwardlytowards the center of the heater. The upper wall of the tubular structure 49 bridges the end walls and makes it unnecessary for the end walls to extend upwardly to the upper wall of the jacket.

The outlet, fitting may be provided with an upper longitudinal deflector 5| to deflect external air currents which may move in a direction from right to left over the top of the heater, as illustrated by Fig. 3, and it may also be provided with end deflectors 52 to shield the outlet orifices from external air currents moving in a direction having a material endwise component with respect to the axis of the heater.

It will be observed that the heater is so positioned as to be shielded by the upper portion of the tie from air currents passing over the tie from left to right as viewed in Fig. 3.

The heater and its outlet attachment are so positioned with respect to the tie that the heated air wlllbe deflected upwardly along the portion of the tie adjacent'the heater and against, the

overlying rails and plates upon which the switchpoints move.

Preferably the jacket of the heater will be provided with two outlet openings one at each side, to one of which an outlet fitting comprising the plate 46 and its associated parts may be secured by screws or other fastening devices 53, and. the other of which may be closed by a cover-plate 54 secured to the jacket by like fastening means. If the heater is to be applied to the side of the tie opposite that to which it is secured as shown in Fig. 3, the outlet fitting and the cover-plate 54 may be readily interchanged so as to establish the desired relation between the outlet orifice of the heater and the adjacent surface of the tie.

The heating coils 28, 20 may be mounted in undercut grooves 55 in blocks or slabs 56, 51, of refractory insulating material, as best illustrated by Figs. 2 and 3. These slabs may be slipped over the coils in an endwise direction and held in their assembled relation in a trough-shaped mounting plate 58 between a pair of stop-lugs 59 at the right-hand end of the mounting plate, as illustrated by Fig. 2, and suitable fastening means such, for example, as the screw and nut 68, 6!, at the left end of the slab 56 as shown in Fig. 4. The trough-like mounting plate 58 with the slabs 56, 51 and heating coils 20, 28' may be inserted endwise in the container 2| and secured to underlying parts of the container by means of appropriate fastening devices. As herein disclosed the right-hand end of the mounting plate as shown in Fig. 2 is fastened to the container by a screw 62 passing through a notch 63 in the plate, and the withdrawal of the plate is prevented by means of a screw 66 as shown at the left end of Fig. 4.

The heating coils may be connected with the terminals of an externally-disposed source of electromotive force by insulated conductors 65 passed through openings in the right-hand end of the container to binding-posts 56 on connecting bars 67, the bars 6'! being provided with a second set of binding-posts 68 for connection with the heating coils. The joints about the conductors 65 where they enter the container may be hermetically sealed and insulated by non-conductive packing material 69 held within stufiingboxes 78 by gland-nuts H.

In the form of the invention herein disclosed as best illustrated by Fig. 2, provision is made whereby the portion 28 of the heating element may be shunted or short-circuited by a thermally-controlled switch 12 having conductive connecting bars 13 mounted on the slab 56 of refractory material and provided with bindingposts 14 to which portions 15 of the heating element uniting the part to be short-circuited with the part to remain in circuit may be connected. The contacts of the switch 12 are normally closed so as to establish a short circuit between the portions 26 of the heating element. Under such circumstances when the conductors 65 of the heater are connected with the source of electromotive force, current will pass directly from one to the other of the two portions 28 of the heating element and the portion 28. will not be energized. As the temperature in the heater increases, the circuit-controlling contacts of the switch 12 will be separated in a manner to be hereinafter explained, after which the short circuit between the connecting portions 15 of the heating element will be broken and current will have to pass in series through the portions 28 of the heating element as well as through portions 28. This inclusion of the portions 20 of the heater in the circuit will increase the resistance and thereby reduce the current strength with a resultant drop in energy in the heater. The ratio of energy to be supplied prior to the opening of the switch 12 to that to be supplied after the switch is open will be dependent upon the ratio of the resistances of the parts 20 and 28 of the heater.

It is the purpose of the switch 12 to normally short-circuit a portion of the heating element in order that when the heater is first energized it may very rapidly be brought up to an efiective heating temperature, after which the temperature may be satisfactorily maintained by cutting in the additional resistance of the portions 28 of the heating coil, thereby reducing the rate of consumption of energy.

One form of thermal switch which is adapted to satisfactorily control the circuits of the heating element in the above-described manner is clearly illustrated by Figs. 4, 5 and 6 of the drawings. The switch comprises essentially two bars 16, T1, of which one has a thermal coefiicient of expansion which is relatively large compared with that of the other, the bars being mounted in a parallel relationship and connected with each other at one end and having their opposite ends connected with switch contacts l8, 19 in such manner that they may be moved towards and from each other as a result of variations in the lengths of the bars due to variations of temperature. In the form of the invention herein disclosed the switch contacts are enclosed within a housing comprising an open-ended cylindrical mounting element 88 having a pair of segmental lugs 8| extended from its closed end 82 and held in contact with upturned ends 83 of the connecting bars 13 (see Figs. 2, 4 and 6) by means of bolts 84 of electrically conductive material and nuts 85, the bolts and nuts also serving as means for clamping the base of the housing between the ends 83 of the bars and the pair of segment-shaped switch contacts 18, and of establishing electrical connections between the bars and contacts.

The member 16 of the thermomotive element of the switch, as best illustrated in Fig. 4, may be of tubular form and may be secured in any appropriate manner, as indicated at 86, to a distended attaching element 81, which may in turn be secured to the housing by means of screws or other suitable fastening means 88, the attaching element having segment-shaped portions cut away to provide the necessary clearance for the lugs 8| of the housing. The member 11 of the thermomotive device may preferably comprise a rod having a threaded connection 89 at one end with the member 16, and the opposite end of the rod may extend through an opening 98 in the housing into the interior where it may be connected with a circuit-closing device 9| adapted to bridge and thereby electrically connect the switch contacts I8. When the parts of the switch are of the form illustrated in Fig. 4 the thermal coefiicient of expansion of the member 11 should be relatively large as compared with that of the member 16, which might approximate a zero coeflicient of expansion or even a negative coefficient. The length of the member I! should be such that at a desired predetermined temperature the circuit-closing element 9| will be in contact with the switch contacts 18, thereby cooperating with the contacts and bolts 84 in establishing a conductive electrical connection between the connector bars 13.

It will be apparent'from the foregoing detailed description of the switch that any increase in temperature of the atmosphere surrounding the thermomotive device 18, 1! will cause the member 11 to be increased in length as compared with the length of .the member 16 and thereby result in a separation of the circuitecloser 9i and switch contacts 18. A decreasein temperature to the predetermined temperature at which the switch is intended to close will restore the electrical connection between the circuit-closer and the switch contacts.

When it is desired to reduce the time element between changes of. temperature of the atmosphere surrounding the thermomotive element and the opening and closing of the switch, the tubular member Iii may be provided with one or more openings 92 to permit air to circulate freely through the thermomotive element and be brought into intimate contact with the highly expansive element 11 so as to communicate heat energy to that element by convection as well as by radiation and conduction.

In order to reduce the undesirable efifect of arcing between the circuit-closer and the switch contacts on opening of the switch, at least one member of each pair of contacting elements may be constructed of carbon; In the form of the invention herein disclosed the contacts 18, 18 may be of copper or other electrically conductive metal, and the circuit-closing element may comprise a disk of carbon 93 of suitable form and dimensions to bridge and close the gap between them. In order that the carbon contact 93? may not have to be unduly massive it may be constructed in the form of a thin disk backed by a disk 96 of copper or other highly conductive material, which, in turn, may be backed by a disk of refractory insulating material reinforced by a disk 95 of metal. The parts 8396 of the circuitcloser may be insulated from and firmly secured to the end of the element H of the thermomotive device in any appropriate manner. As hereindisclosed the elements 93, 9Q, 95 are mounted upon a sleeve of refractory insulating material 97, which may be clamped between a metal washer 98 bearing against a shoulder 99 on the element 11'! and the metal reinforcing plate 96 by means of nuts I00 threaded to the end of the rod H.

The housing element 86 of refractory insulat ing material may be enclosed within and armored by a metal cap Iill, which may be threaded to or otherwise connected with the periphery of the distended attaching element 81 of the thermomotive device, which may be extended sufficiently beyond the wall of the housing to be available for such purpose. sure formed by the cap [BI and the attaching element of the thermomotive device may be completed by inserting a disk I02 of mica or other suitable insulating material between the inner end wall of the cap and the housing, and the heads of the screws 88 may be insulated from the interior of the switch housing by means of a disk I03 of mica or other suitable insulating material. The connecting bars 13 may be firmly secured to the slab of refractory insulating material 56 by means of the binding-posts 14 reinforced by any necessary additional attaching elements, such, for example, as screws I04 (Fig. 4).

In Fig. 9 is illustrated a modified form of ther-' momotive device having-means whereby the lag of the time element in accordance with which the operation of the switch will follow changes of temperature of thesurrounding atmosphere may The insulation of the enclobe readily adjusted. In this form of the invention the member 16 of the thermomotive element is surrounded by a sleeve I05 of any appropriate material, which may be carried by a cap I06 having a. threaded connection with a tapped extension 10! of the member 11 of the thermomotive device. This sleeve I05 will more or less retard the communication to member 7! of the thermomotive element of variations of temperature of the surrounding atmosphere, depending upon the extent to which the sleeve is caused to envelop the tube 16. The sleeve would have such a retarding'effect, irrespective of the presence of openings 92 in the tube and its efiect upon such openings, merely because of the added mass of material to and through which heat energy would have to be communicated and transmitted to the rod 11. The sleeve I55 may also, and perhaps more efiectively, control the time element of the thermomotive device in that it may open and close in succession any number of the air inlet and outlet openings 92 so as to increase and decrease the effectiveness of air circulation through the thermomotive device. The sleeve I05 may be of metal or of asbestos, or of any other suitable material.

After the adjustment of the time element of the thermomotive device has been efiected by the proper setting of the position of the sleeve IE5, if it is desired that such adjustment be permanent, the threaded end 01 of the rod 71 may be cut off and the metal parts at the end of the threaded connection burred or mutilated in such manner as to prevent relative rotation. the rod N of the thermomotive device of either form of the invention disclosed has been adjusted with respect to the tubular element '76 so as to cause the circuit-closer to make contact with the switch contacts 18, 79, at the desired temperature, the adjustment may be made permanent in any appropriate manner as by mutilating the material at the end of the threaded connection 89 with the aid of a center punch.

It will be apparent from the foregoing description that the parts of the heater and its controlling switch .may be readily constructed and assembled and disassembled. When assembled all of the electrical parts of the heater are hermetically sealed within the container 2! by the caps 22 and 23 and by the insulated packing surrounding the openings through which the conductors 65 enter the container.

The assembled heaters may be readily secured to either side of each of a number of ties in the vicinity of a railroad switch in groups and so distributed as to most effectively keep the spaces between the switch-points and the service rails free of snow and ice. By selectively using the lugs 2?.

at opposite sides of the heater in connecting it with the mounting bars 30, and byinterchanging the outlet fittings 26' and cover-plates 54, the heaters may be very quickly shifted from one side of a tie to the other or reversed endwise in order to facilitate their connection with electrical conductors through which they are supplied with energy and to insure their location in the positions with respect tothe switch-points, bearing plates and rails which will be most effective.

The control of the device by the automatic, adjustable, thermal switch is such that the heater may be very quickly rendered effective due to the preliminary short-circuiting of the inner heating coilsZi), and the rate of supply of energy to the heater will then be automatically reduced to an.

extent such as to maintain the heater at a satisfactory working temperature. To continuously maintain the heater at a temperature such as would be practical when first putting it into operation would result in a very material waste of energy, whereas the supply of energy at a rate such as would be satisfactory after it has been brought up to a working temperature would not be sufficient to promptly and efficiently establish its working temperature when first thrown into service.

The invention is not intended to be limited to the particular forms which have been selected for purposes of illustration, but should be regarded as including modifications and variations thereof within the scope of the appended claims.

What is claimed is:-

1. An electric railway track and track-switch heater comprising a closed container, an electric heating element sealed in the container, means whereby the heating element may be energized from an externally-disposed source of electromotive force, a jacket surrounding the container, inlet and outlet openings so positioned in the walls of the jacket as to cause air to be drawn into the jacket, heated and ejected from the jacket when the heating element is energized, and means for mounting the heater in a position such that air ejected from the heater will be directed against the part of the railway track construction tobe heated.

2. An electric railway track and track-switch heater, like that defined by claim 1, of which the container and the jacket are of tubular form having substantially concentric cylindrical walls separated by an intervening air space, the air inlet being in the lower portion of an end wall of the jacket and the air outlet in the upper portion of its cylindrical Wall.

3. An electric railway track and track-switch heater, like that defined by claim 1, having its air outlet in the upper part of the jacket, the outlet orifice being located at one side of a vertical plane passing through the center of the heater, the jacket having a baiile-plate extending from the lower margin of the outlet orifice into the space between the walls of the jacket and the container towards and approximately to the aforesaid plane, the bafile-plate being spaced intermediate said walls so that air may pass under the same, around its inner end and then over the same to and through the orifice.

4. An electric railway track and track-switch heater, like that defined by claim 1, having its air outlet in the upper part of the jacket at one side of a vertical plane passing through the center of the heater, the jacket being provided with a bafile-plate extending from the lower margin of the outlet orifice into the space between the walls of the jacket and the container towards and approximately to the aforesaid vertical plane, the plate being spaced intermediate the walls of the jacket and the container and the space over the plate being walled in at the top and ends from the upper and end margins of the orifice so as to form a laterally-directed conduit from the upper central part of the jacketed part of the heater to the outlet orifice.

5. An electric railway track and track-switch heater like the one defined by claim 1, of which the heating equipment comprises an electric conductor of a resistance such as to render it appropriate for use as a heating element when connected between the terminals of a source of electromotive force, an electric switch, low-resistance conductors connecting the terminals of said switch in parallel with a portion of the heating element, the switch and the portion of the heating element with which it is connected in parallel being connected in series with the remainder of the heating element, so that the portion of the heating element in parallel with the switch may be shunted by a highly conductive connection by closing the switch terminals, and a thermomotive device within the temperature-modifying range of the electric heater to open the switch when the temperature of the device is raised above a predetermined temperature and to close the switch when the temperature of the device falls below a predetermined temperature.

6. An electric railway track and track-switch heater, like that defined by claim 1, having as a means for directing air ejected from the heater against the part of the railway track construction to be heated, an upwardly and outwardly directed balile-plate extending from the upper margin of its outlet orifice.

7. An electric railway track and track-switch heater, as defined by claim 1, having as a means for directing air ejected from the heater against the part of the railway track construction to be heated, a pair of outwardly-directed baffle-plates extending from the end margins of its outlet orifice.

WILLIAM P. SCHOLZ. 

